1. Field of the Invention
The present invention relates to medical devices, and, more particularly, to a marker delivery device for percutaneous tissue marker placement.
2. Description of the Related Art
Tissue biopsies are commonly performed on many areas and organs of the human body where it is desirable to ascertain whether or not a lesion or other tissue to be biopsied is cancerous. Often, the lesion or other tissue to be biopsied is identified through use of an imaging technique, such as a computerized axial tomography (CAT) scan, ultrasonography, and mammography.
In breast biopsies, for example, the lesion typically is so small that the biopsy reduces its size to the extent that it is no longer visible by the imaging method employed. In such circumstances, it is desirable to place a tissue marker at the site of the biopsy to enable the medical practitioner subsequently to locate the lesion quickly and accurately in the event complete removal of the affected tissue is indicated. The tissue marker is placed at the biopsy site, for example, by a marker delivery device having a needle cannula that houses the tissue marker.
In some marker delivery devices, the marker may not be completely ejected from the cannula, or may be drawn back into or toward the cannula by the vacuum created upon the withdrawal of the cannula, which results in the marker being moved from the intended site, leading to inaccurate identification of the location of the biopsy area. Another issue is the safe disposal of the marker delivery device after use, particularly the safe disposal of the cannula portion of the marker delivery device that is inserted into the tissue of the patient, which typically has a sharp point.